This invention relates to a chewing gum base containing a thermally decomposed product of a natural rubber and if desired a milled natural rubber, and to a method of preparing the same. The thermally decomposed product is freed from low-boiling substances.
Heretofore, a synthetic resin such as polyvinyl acetate resin or a natural material such as chicle, jelutong or the like has been used as a chewing gum base. The synthetic gum base made essentially from the vinyl acetate resin entails such disadvantages that the chewing fum prepared therefrom is rapidly softened by incorporating a saliva under chewing and that the flavor of the chewing gum is readily dissolved out since the gum base of this type possesses a relatively high hydrophilic nature. Therefore, a natural resinous material such as chicle, jelutong, sorba or the like has been advantageously used as the chewing gum base, and among others the chicle has been considered most advantageous.
These natural resinous materials, however, have not been successfully cultivated, so that the prices are high and the natural resources are limited in future.
On the contrary, a natural rubber of high elasticity has been profitably cultivated and is easily available at low price, so that it has been used in a great amount for the use requiring high elasticity such as a tire. The natural rubber, however, has never been used as a chewing gum base.
The inventors have earnestly endeavored to prepare a chewing gum base having a better softening property under chewing and also having a better retention of the flavors of the chewing gum by the use of the natural rubber which is abundant in natural resources and is available at low price, and have now succeeded in preparing the chewing gum base having the better properties than those of the conventional synthetic gum base by incorporating a thermally decomposed product of the natural rubber and if desired a milled natural rubber into basic materials for the chewing gum.
The Japanese opened applications No. 76239/75, No. 77301/75 and No. 10013/76 disclose the methods for preparation of hydrocarbons by the thermal decomposition of synthetic polyisoprene rubber or natural rubber and also disclose that the saturated hydrocarbons prepared by the above methods may be used in the cosmetics. Up to now, however, it has been unknown to use the thermally decomposed products of the synthetic or natural rubbers for the foods, especially for the chewing gum.